Sam Rockwell and Saoirse Ronan have great chemistry in this amusing parody of Agatha Christie stories. She plays "Stalker," an eager young officer paired with the seasoned, fondness-for-gin inspector "Stoppard" when the unpleasant film director "Köpernick" (Adrien Brody) is murdered with a sewing machine. It’s revealed that he had recently gotten engaged to direct a movie adaptation of the famous play "Mousetrap," which was marking its hundredth performance at London's Ambassador's Theatre. What follows is a captivating mystery, full of flashbacks, as the two police officers must learn to work together while navigating the heightened emotions among a group of actors, an ambitious producer, and a publicity-hungry police Commissioner. Rockwell gives a solid performance as the quiet and world-weary officer—he brought to mind Johnny Depp’s “Abberline” in "From Hell" from 2001—and Ronan adds plenty of humor (along with bravery) to her role as his eager partner, who frequently makes hasty judgments. As is typical with Christie narratives, you just know the person responsible for the crime will be the least significant character, so there isn’t a great deal of suspense here, but things conclude positively in an old manor house where it ultimately comes down to the author—"Moaning Myrtle" herself—to resolve her own puzzle. Tom George has gathered a respectable supporting cast; Harris Dickinson is quite good as a rather delicate Richard Attenborough and Ruth Wilson portrays the clever theatre producer "Petula," contributing to a pace and humor that's pleasantly agreeable for just over ninety minutes. I’ve often dined at the Ivy restaurant across from this theater, but have never actually seen the play. Similar to this film, you shouldn't give away the ending or you might be next! It was enjoyable.

Source on TMDB